PDBsum entry 4by5

Calcium-binding protein

PDB id: 4by5

Contents

Protein chains

171 a.a.

180 a.a.

Metals

_CA ×12

_NA

Waters ×227

PDB id:

4by5

Name:

Calcium-binding protein

Title:

Crystal structure of drosophila frq2

Structure:

Fi18190p1. Chain: a, b, c, d. Synonym: frequenin, frequenin 2. Engineered: yes. Mutation: yes. Other_details: calcium binding to ef hands 2,3 and 4

Source:

Drosophila melanogaster. Fruit fly. Organism_taxid: 7227. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.22Å R-factor: 0.214 R-free: 0.271

Authors:

S.Banos-Mateos,A.Chaves-Sanjuan,M.J.Sanchez-Barrena

Key ref:

J.Romero-Pozuelo et al. (2014). The guanine-exchange factor Ric8a binds to the Ca²⁺ sensor NCS-1 to regulate synapse number and neurotransmitter release. J Cell Sci, 127, 4246-4259. PubMed id: 25074811 DOI: 10.1242/jcs.152603

Date:

17-Jul-13 Release date: 13-Aug-14

Protein chains

Q9VWX8  (Q9VWX8_DROME) -  Frequenin-2 from Drosophila melanogaster

Seq: 187 a.a.

Struc: 171 a.a.*

Protein chain

Q9VWX8  (Q9VWX8_DROME) -  Frequenin-2 from Drosophila melanogaster

Seq: 187 a.a.

Struc: 180 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

DOI no: 10.1242/jcs.152603

J Cell Sci 127:4246-4259 (2014)

PubMed id: 25074811

The guanine-exchange factor Ric8a binds to the Ca²⁺ sensor NCS-1 to regulate synapse number and neurotransmitter release.

J.Romero-Pozuelo, J.S.Dason, A.Mansilla, S.Baños-Mateos, J.L.Sardina, A.Chaves-Sanjuán, J.Jurado-Gómez, E.Santana, H.L.Atwood, �.�.Hernández-Hernández, M.J.Sánchez-Barrena, A.Ferrús.

ABSTRACT

The conserved Ca(2+)-binding protein Frequenin (homolog of the mammalian NCS-1, neural calcium sensor) is involved in pathologies that result from abnormal synapse number and probability of neurotransmitter release per synapse. Both synaptic features are likely to be co-regulated but the intervening mechanisms remain poorly understood. We show here that Drosophila Ric8a (a homolog of mammalian synembryn, which is also known as Ric8a), a receptor-independent activator of G protein complexes, binds to Frq2 but not to the virtually identical homolog Frq1. Based on crystallographic data on Frq2 and site-directed mutagenesis on Frq1, the differential amino acids R94 and T138 account for this specificity. Human NCS-1 and Ric8a reproduce the binding and maintain the structural requirements at these key positions. Drosophila Ric8a and Gαs regulate synapse number and neurotransmitter release, and both are functionally linked to Frq2. Frq2 negatively regulates Ric8a to control synapse number. However, the regulation of neurotransmitter release by Ric8a is independent of Frq2 binding. Thus, the antagonistic regulation of these two synaptic properties shares a common pathway, Frq2-Ric8a-Gαs, which diverges downstream. These mechanisms expose the Frq2-Ric8a interacting surface as a potential pharmacological target for NCS-1-related diseases and provide key data towards the corresponding drug design.